Wait, you said I need to space further out, but that it misses because I'm not close enough? Not sure what you mean.
Also, it's on Jin. Trying the:
4B+C,itsuuA,dash 6C,C,jB,C,]D[,airdash C,staff2,6C,tsubame,6C combo. I've tried waiting a sec before doing tsubame, dashing for the first 6C after staff2, and just doing it all right away. Still feels random lol.